Let's roll up our sleeves and solve this. We have 833 and we're going to multiply it by 51, essentially adding 833 to itself 51 times.
Step 1: 0 + 833 = 833
Step 2: 833 + 833 = 1666
Step 3: 1666 + 833 = 2499
Step 4: 2499 + 833 = 3332
Step 5: 3332 + 833 = 4165
Step 6: 4165 + 833 = 4998
Step 7: 4998 + 833 = 5831
Step 8: 5831 + 833 = 6664
Step 9: 6664 + 833 = 7497
Step 10: 7497 + 833 = 8330
Step 11: 8330 + 833 = 9163
Step 12: 9163 + 833 = 9996
Step 13: 9996 + 833 = 10829
Step 14: 10829 + 833 = 11662
Step 15: 11662 + 833 = 12495
Step 16: 12495 + 833 = 13328
Step 17: 13328 + 833 = 14161
Step 18: 14161 + 833 = 14994
Step 19: 14994 + 833 = 15827
Step 20: 15827 + 833 = 16660
Step 21: 16660 + 833 = 17493
Step 22: 17493 + 833 = 18326
Step 23: 18326 + 833 = 19159
Step 24: 19159 + 833 = 19992
Step 25: 19992 + 833 = 20825
Step 26: 20825 + 833 = 21658
Step 27: 21658 + 833 = 22491
Step 28: 22491 + 833 = 23324
Step 29: 23324 + 833 = 24157
Step 30: 24157 + 833 = 24990
Step 31: 24990 + 833 = 25823
Step 32: 25823 + 833 = 26656
Step 33: 26656 + 833 = 27489
Step 34: 27489 + 833 = 28322
Step 35: 28322 + 833 = 29155
Step 36: 29155 + 833 = 29988
Step 37: 29988 + 833 = 30821
Step 38: 30821 + 833 = 31654
Step 39: 31654 + 833 = 32487
Step 40: 32487 + 833 = 33320
Step 41: 33320 + 833 = 34153
Step 42: 34153 + 833 = 34986
Step 43: 34986 + 833 = 35819
Step 44: 35819 + 833 = 36652
Step 45: 36652 + 833 = 37485
Step 46: 37485 + 833 = 38318
Step 47: 38318 + 833 = 39151
Step 48: 39151 + 833 = 39984
Step 49: 39984 + 833 = 40817
Step 50: 40817 + 833 = 41650
Step 51: 41650 + 833 = 42483

So, 833*51 = 42483